We’ve all heard the idiom, “don’t judge a book by its cover.” But a new site called PlayJudgey.com encourages users to do just that—and its creators, Nate Gagnon and Dean Casalena, seem to have a moral of their own in mind: buy more books.

The site displays a book cover, which you then rate on a scale topping out at 5 stars. The twist is that after submitting your judgement, Judgey grabs the average Goodreads score and compares the two ratings. If you’ve not read the book—or you have an opinion that doesn’t align with the average—your score will likely be far off from Goodreads. If you have read it—or you’re just a good guesser—your rating might align better and the end note will be a little less snotty.

Throughout the game, the site will politely prompt you from the top-left corner to buy the book. So while it’s fun to see how your tastes in cover art match up with how books are received for their content, it’s also a great way to discover new reads. Play it here.